Week 8 Flashcards
What are the functions of the kidneys?
- Filtration of plasma
- Resorption of water and electrolytes
- Blood pressure
- Production of erythropoietin: stimulates the production of red blood cells
- Production of Vitamin D
- Gluconeogenesis: creation of glucoses from smaller, noncarbon source
- Acid base balance
- Excretion of waste products
How many kidneys?
- which is lower
- which has longer renal vein
- preferred for donation
- right; bc of liver
- left
- left
Parts of a nehron
- glomerulus
- bowmans capsule
- PCT
- Loop of Henle
- DCT
- collecting duct
Types of nephrons
- location of glomerulus
- loop of henle
- peritubular capillaries
- cortical and juxtamedullary
- both in the cortex
- C: mostly in cortex, barely dips into the medulla; J: completely in the medulla
- C: does not have venule end; J: has venule end
Juxtaglomerular apparatus
- components
- podocytes
- granular cells that release renin
- macula densa with Na, Cl-
- Efferent and Afferent arterioles
- Medangial cells; phagocytic
Granular cells
- location
- make?
- type of cell
- Located on the afferent arterioles
- They contain vesicles, and inside are renin
- modified vascular smooth muscle cells of afferent arterioles
Mesangial cells
- what are they?
- phagocytic cells/ modified macrophage
Macula densa cells
- location
- what are they?
- job?
- junction of DCT and peak ascending arteriole limb
- modified epithelial cells
- transporters; have potassium, sodium, chloride transporters
Basic renal processes (4)
Filtration, secretion, reabsorption, excretion
Excretion versus secretion
- Excretion is what leaves the body– into urine
- Tubular secretion is released into tubular fluid
When cells of the renal tubules secrete the drug penicillin, is the drug being added to or removed from the bloodstream
What happens after?
- Secreted; the drug is being removed from blood stream and into the tubule fluid
- The substances can also be reabsorbed after secretion, depends on the substances on whether they are secreted or excreted
Why is it called reabsorption
- The second time being absorbed– first time is in the gut
- Those substances are absorbed first in the GI tract
what component of the filtration membrane damaged resulting in hematuria?
endothelial cells of the capillaries; usually the fenestrations
component of filtration membrane damaged resulting in proteinuria?
basement membrane; specifically heparin sulfate and glycoproteins
Student w/ hematuria 1 wk after pharyngitis w/ elevated BP , BUN, and serum creatinine. Positive for RBC casts and dysmorphic RBC in urine.
- what condition? why?
- cause
- key features?
- nephritic syndrome bc of the blood in the urine
- cross-reactivity between the Abs from streptococcus and the fenestrated glomerular cells so there is damage to the glomerular endothelial cells
- HTN, arguably oligouria, dysmorphic RBCs and casts found in urine.
56 yr old male with edema, weight gain, ascites, and S3 galllop. Serum showed elevated Na and lipids and low albumin
- condition. why?
- pahthophysiology behind edema and proteinuria?
- patho behind hyperlipidemia
- nephrotic syndrome; Bc of the edema and lots of proteins in the urine
- capillary walls have increased permeability to proteins
- when there’s low oncotic pressure liver is stimulated to produce more proteins and also loss of lipids in urine favors production of lipoproteins so lipids can bind to them. Liver does produce albumin as well but here we are talking abut the connection between the lipids/hyperlipidemia.
Nephritic syndrome
- pathogen
- features
- inflammation of the glomerulus damaging the fenestration in capillary endothelium
- Hematuria and RBC casts in urine
Nephrotic Syndrome
- loss of nephrin and negative charges on the glomerular filtration
- proeinuria, edenam hyperlipidemia
Units for GFR
- normal range
- mL/min OR L/hr OR L/day
- 80-120 mL/min
Formula to calculate GFR
clearance=urine concentration*volume of urine flow rate/ plasma concentration of substance
best substance to use to measure GFR?
- It cannot be secreted, reabsorbed, metabolize or synthesized but can be freely filtered
What directly determines GFR?
- what favors filtration?
- what opposes filtration?
- what can happen with tumor obstructing R ureter? Would anything happen to the L Kidney?
- glomerular capillary blood pressure
- fluid pressure in bowmans space (the fluid backing up as it funnels down) and osmotic pressure in capillary bc of protein left behind
- It would cause a decrease in filtration because it would increase the fluid pressure in bowmans capsule; L kidney would be unaffected
Renal blood flow
aorta -> renal a -> segmental a -> interlobar a -> arcuate a -> cortical radiate a -> afferent a -> glomerulus -> efferent a -> peritubular capillaries/vasa recta -> cortical radiate v -> arcuate v -> interlobar v -> renal v -> IVC
role of arterioles?
- controlled by?
- what happens if renal arteriole constricts?
- they constrict to modulate blood flow
- autonomic NS
- GFR decreases and there is more time for substances to be reabsorbed